Résumé
We report a polarization-resolved analysis of the second harmonic intensity collected in retro-reflection from a Lithium Niobate microcrystals powder. Depth intensity profiles exhibit first an increase due to the beam focus entering the powder then a decrease due to multiple scattering. With a polarization analysis performed at selected depths, we show that there is a competition between ballistic and multiply scattered photons. The contribution from the multiply scattered photons dominates at all depths whereas, at the maximum of the intensity depth profiles, the contribution of the ballistic photons is at its maximum and enhanced due to collection efficiency. This latter contribution from the ballistic photons is clearly observed through distortions in the polarization-resolved plots.
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•The combined analysis resulting from the depth profiling of the polarization-resolved powder second harmonic generation is here highlighted.•The SHG intensity results from the superposition of the ballistic and multiply scattered photons contributions.•The contribution from the multiply scattered photons dominates at all depths.•At the air/powder interface, the ballistic photons contributions are enhanced and thus comparable to the multiply contribution.